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Homma K. The Pathological Mechanisms of Hearing Loss Caused by KCNQ1 and KCNQ4 Variants. Biomedicines 2022; 10:biomedicines10092254. [PMID: 36140355 PMCID: PMC9496569 DOI: 10.3390/biomedicines10092254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 09/08/2022] [Accepted: 09/09/2022] [Indexed: 11/29/2022] Open
Abstract
Deafness-associated genes KCNQ1 (also associated with heart diseases) and KCNQ4 (only associated with hearing loss) encode the homotetrameric voltage-gated potassium ion channels Kv7.1 and Kv7.4, respectively. To date, over 700 KCNQ1 and over 70 KCNQ4 variants have been identified in patients. The vast majority of these variants are inherited dominantly, and their pathogenicity is often explained by dominant-negative inhibition or haploinsufficiency. Our recent study unexpectedly identified cell-death-inducing cytotoxicity in several Kv7.1 and Kv7.4 variants. Elucidation of this cytotoxicity mechanism and identification of its modifiers (drugs) have great potential for aiding the development of a novel pharmacological strategy against many pathogenic KCNQ variants. The purpose of this review is to disseminate this emerging pathological role of Kv7 variants and to underscore the importance of experimentally characterizing disease-associated variants.
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Affiliation(s)
- Kazuaki Homma
- Department of Otolaryngology-Head and Neck Surgery, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; ; Tel.: +1-312-503-5344
- The Hugh Knowles Center for Clinical and Basic Science in Hearing and Its Disorders, Northwestern University, Evanston, IL 60608, USA
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2
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Abstract
Kv7.1-Kv7.5 (KCNQ1-5) K+ channels are voltage-gated K+ channels with major roles in neurons, muscle cells and epithelia where they underlie physiologically important K+ currents, such as neuronal M current and cardiac IKs. Specific biophysical properties of Kv7 channels make them particularly well placed to control the activity of excitable cells. Indeed, these channels often work as 'excitability breaks' and are targeted by various hormones and modulators to regulate cellular activity outputs. Genetic deficiencies in all five KCNQ genes result in human excitability disorders, including epilepsy, arrhythmias, deafness and some others. Not surprisingly, this channel family attracts considerable attention as potential drug targets. Here we will review biophysical properties and tissue expression profile of Kv7 channels, discuss recent advances in the understanding of their structure as well as their role in various neurological, cardiovascular and other diseases and pathologies. We will also consider a scope for therapeutic targeting of Kv7 channels for treatment of the above health conditions.
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Amirian A, Zafari Z, Dalili M, Saber S, Karimipoor M, Dabbagh Bagheri S, Fazelifar AF, Zeinali S. Detection of a new KCNQ1 frameshift mutation associated with Jervell and Lange-Nielsen syndrome in 2 Iranian families. J Arrhythm 2018; 34:286-290. [PMID: 29951145 PMCID: PMC6010008 DOI: 10.1002/joa3.12042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/20/2018] [Indexed: 12/22/2022] Open
Abstract
Jervell-Lange Nielsen syndrome (JLNS) with autosomal recessive inheritance is a congenital cardiovascular disorder characterized by prolongation of QT interval on the ECG and deafness. We have performed molecular investigation by haplotype analysis and DNA Sanger sequencing in 2 unrelated Iranian families with a history of syncope. Mutational screening of KCNQ1 gene revealed the novel homozygous frameshift mutation c.733-734delGG (p.G245Rfs*39) in 2 obviously unrelated cases of JLNS which is probably a founder mutation in Iran. The novel mutation detected in this study is the first time reported among Iranian population and will be beneficial in the tribe and region-specific cascade screening of LQTS in Iran.
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Affiliation(s)
- Azam Amirian
- Biotechnology Research CenterPasteur Institute of IranTehranIran
| | - Zahra Zafari
- Department of Medical GeneticsFaculty of Medical SciencesTarbiat Modares UniversityTehranIran
| | - Mohammad Dalili
- Cardiac Electrophysiology Research CenterRajaie Cardiovascular Medical, and Research CenterIran University of Medical SciencesTehranIran
| | - Siamak Saber
- Cardiac Electrophysiology Research CenterRajaie Cardiovascular Medical, and Research CenterIran University of Medical SciencesTehranIran
| | | | | | - Amir Farjam Fazelifar
- Cardiac Electrophysiology Research CenterRajaie Cardiovascular Medical, and Research CenterIran University of Medical SciencesTehranIran
| | - Sirous Zeinali
- Biotechnology Research CenterPasteur Institute of IranTehranIran
- Medical Genetics LaboratoryKawsar Human Genetics Research CenterTehranIran
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4
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Bersell K, Montgomery JA, Kanagasundram AN, Campbell CM, Chung WK, Macaya D, Konecki D, Venter E, Shoemaker MB, Roden DM. Partial Duplication and Poly(A) Insertion in KCNQ1 Not Detected by Next-Generation Sequencing in Jervell and Lange-Nielsen Syndrome. Circ Arrhythm Electrophysiol 2016; 9:CIRCEP.116.004081. [PMID: 27286732 DOI: 10.1161/circep.116.004081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 05/03/2016] [Indexed: 11/16/2022]
Affiliation(s)
- Kevin Bersell
- From the Departments of Pharmacology (K.B.), Medicine (J.A.M., A.N.K., C.M.C., M.B.S., D.M.R.), Biomedical Informatics (D.M.R.), Vanderbilt University, Nashville, TN; Departments of Pediatrics (W.K.C.), Medicine (W.K.C.), Columbia University Medical Center, New York, NY; and GeneDx, Gaithersburg, MD (D.M., D.K., E.V.)
| | - Jay A Montgomery
- From the Departments of Pharmacology (K.B.), Medicine (J.A.M., A.N.K., C.M.C., M.B.S., D.M.R.), Biomedical Informatics (D.M.R.), Vanderbilt University, Nashville, TN; Departments of Pediatrics (W.K.C.), Medicine (W.K.C.), Columbia University Medical Center, New York, NY; and GeneDx, Gaithersburg, MD (D.M., D.K., E.V.)
| | - Arvindh N Kanagasundram
- From the Departments of Pharmacology (K.B.), Medicine (J.A.M., A.N.K., C.M.C., M.B.S., D.M.R.), Biomedical Informatics (D.M.R.), Vanderbilt University, Nashville, TN; Departments of Pediatrics (W.K.C.), Medicine (W.K.C.), Columbia University Medical Center, New York, NY; and GeneDx, Gaithersburg, MD (D.M., D.K., E.V.)
| | - Courtney M Campbell
- From the Departments of Pharmacology (K.B.), Medicine (J.A.M., A.N.K., C.M.C., M.B.S., D.M.R.), Biomedical Informatics (D.M.R.), Vanderbilt University, Nashville, TN; Departments of Pediatrics (W.K.C.), Medicine (W.K.C.), Columbia University Medical Center, New York, NY; and GeneDx, Gaithersburg, MD (D.M., D.K., E.V.)
| | - Wendy K Chung
- From the Departments of Pharmacology (K.B.), Medicine (J.A.M., A.N.K., C.M.C., M.B.S., D.M.R.), Biomedical Informatics (D.M.R.), Vanderbilt University, Nashville, TN; Departments of Pediatrics (W.K.C.), Medicine (W.K.C.), Columbia University Medical Center, New York, NY; and GeneDx, Gaithersburg, MD (D.M., D.K., E.V.)
| | - Daniela Macaya
- From the Departments of Pharmacology (K.B.), Medicine (J.A.M., A.N.K., C.M.C., M.B.S., D.M.R.), Biomedical Informatics (D.M.R.), Vanderbilt University, Nashville, TN; Departments of Pediatrics (W.K.C.), Medicine (W.K.C.), Columbia University Medical Center, New York, NY; and GeneDx, Gaithersburg, MD (D.M., D.K., E.V.)
| | - David Konecki
- From the Departments of Pharmacology (K.B.), Medicine (J.A.M., A.N.K., C.M.C., M.B.S., D.M.R.), Biomedical Informatics (D.M.R.), Vanderbilt University, Nashville, TN; Departments of Pediatrics (W.K.C.), Medicine (W.K.C.), Columbia University Medical Center, New York, NY; and GeneDx, Gaithersburg, MD (D.M., D.K., E.V.)
| | - Eli Venter
- From the Departments of Pharmacology (K.B.), Medicine (J.A.M., A.N.K., C.M.C., M.B.S., D.M.R.), Biomedical Informatics (D.M.R.), Vanderbilt University, Nashville, TN; Departments of Pediatrics (W.K.C.), Medicine (W.K.C.), Columbia University Medical Center, New York, NY; and GeneDx, Gaithersburg, MD (D.M., D.K., E.V.)
| | - M Benjamin Shoemaker
- From the Departments of Pharmacology (K.B.), Medicine (J.A.M., A.N.K., C.M.C., M.B.S., D.M.R.), Biomedical Informatics (D.M.R.), Vanderbilt University, Nashville, TN; Departments of Pediatrics (W.K.C.), Medicine (W.K.C.), Columbia University Medical Center, New York, NY; and GeneDx, Gaithersburg, MD (D.M., D.K., E.V.)
| | - Dan M Roden
- From the Departments of Pharmacology (K.B.), Medicine (J.A.M., A.N.K., C.M.C., M.B.S., D.M.R.), Biomedical Informatics (D.M.R.), Vanderbilt University, Nashville, TN; Departments of Pediatrics (W.K.C.), Medicine (W.K.C.), Columbia University Medical Center, New York, NY; and GeneDx, Gaithersburg, MD (D.M., D.K., E.V.).
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Ruwald MH, Xu Parks X, Moss AJ, Zareba W, Baman J, McNitt S, Kanters JK, Shimizu W, Wilde AA, Jons C, Lopes CM. Stop-codon and C-terminal nonsense mutations are associated with a lower risk of cardiac events in patients with long QT syndrome type 1. Heart Rhythm 2015; 13:122-31. [PMID: 26318259 DOI: 10.1016/j.hrthm.2015.08.033] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND In long QT syndrome type 1 (LQT1), the location and type of mutations have been shown to affect the clinical outcome. Although haploinsufficiency, including stop-codon and frameshift mutations, has been associated with a lower risk of cardiac events in patients with LQT1, nonsense mutations have been presumed functionally equivalent. OBJECTIVE The purpose of this study was to evaluate clinical differences between patients with nonsense mutations. METHODS The study sample comprised 1090 patients with genetically confirmed mutations. Patients were categorized into 5 groups, depending on mutation type and location: missense not located in the high-risk cytoplasmic loop (c-loop) (n = 698), which is used as reference; missense c-loop (n = 192); stop-codon (n = 67); frameshift (n = 39); and others (n = 94). The primary outcome was a composite end point of syncope, aborted cardiac arrest, and long QT syndrome-related death (cardiac events). Outcomes were evaluated using the multivariate Cox proportional hazards regression analysis. Standard patch clamp techniques were used. RESULTS Compared to patients with missense non-c-loop mutations, the risk of cardiac events was reduced significantly in patients with stop-codon mutations (hazard ratio [HR] 0.57; 95% confidence interval [CI] 0.34-0.96; P = .035), but not in patients with frameshift mutations (HR 1.01; 95% CI 0.58-1.77; P = .97). Our data suggest that currents of the most common stop-codon mutant channel (Q530X) were larger than those of haploinsufficient channels (wild type: 42 ± 6 pA/pF, n = 20; Q530X+wild type: 79 ± 14 pA/pF, n = 20; P < .05) and voltage dependence of activation was altered. CONCLUSION Stop-codon mutations are associated with a lower risk of cardiac events in patients with LQT1, while frameshift mutations are associated with the same risk as the majority of the missense mutations. Our data indicate functional differences between these previously considered equivalent mutation subtypes.
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Affiliation(s)
- Martin H Ruwald
- Heart Research Follow-up Program, Division of Cardiology, University of Rochester Medical Center, Rochester, New York; Department of Cardiology, Gentofte Hospital, Hellerup, Denmark
| | - Xiaorong Xu Parks
- Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York
| | - Arthur J Moss
- Heart Research Follow-up Program, Division of Cardiology, University of Rochester Medical Center, Rochester, New York
| | - Wojciech Zareba
- Heart Research Follow-up Program, Division of Cardiology, University of Rochester Medical Center, Rochester, New York
| | - Jayson Baman
- Heart Research Follow-up Program, Division of Cardiology, University of Rochester Medical Center, Rochester, New York
| | - Scott McNitt
- Heart Research Follow-up Program, Division of Cardiology, University of Rochester Medical Center, Rochester, New York
| | - Jorgen K Kanters
- Department of Cardiology, Gentofte Hospital, Hellerup, Denmark; Laboratory of Experimental Cardiology, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Wataru Shimizu
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Arthur A Wilde
- AMC Heart Centre, Department of Clinical and Experimental Cardiology, Academic Medical Centre, Amsterdam, The Netherlands
| | - Christian Jons
- Department of Cardiology, Gentofte Hospital, Hellerup, Denmark
| | - Coeli M Lopes
- Cardiovascular Research Institute, Department of Medicine, University of Rochester, Rochester, New York.
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Mousavi Nik A, Gharaie S, Jeong Kim H. Cellular mechanisms of mutations in Kv7.1: auditory functions in Jervell and Lange-Nielsen syndrome vs. Romano-Ward syndrome. Front Cell Neurosci 2015; 9:32. [PMID: 25705178 PMCID: PMC4319400 DOI: 10.3389/fncel.2015.00032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 01/19/2015] [Indexed: 01/06/2023] Open
Abstract
As a result of cell-specific functions of voltage-activated K+ channels, such as Kv7.1, mutations in this channel produce profound cardiac and auditory defects. At the same time, the massive diversity of K+ channels allows for compensatory substitution of mutant channels by other functional channels of their type to minimize defective phenotypes. Kv7.1 represents a clear example of such functional dichotomy. While several point mutations in the channel result in a cardio-auditory syndrome called Jervell and Lange-Nielsen syndrome (JLNS), about 100-fold mutations result in long QT syndrome (LQTS) denoted as Romano–Ward syndrome (RWS), which has an intact auditory phenotype. To determine whether the cellular mechanisms for the diverse phenotypic outcome of Kv7.1 mutations, are dependent on the tissue-specific function of the channel and/or specialized functions of the channel, we made series of point mutations in hKv7.1 ascribed to JLNS and RWS. For JLNS mutations, all except W248F yielded non-functional channels when expressed alone. Although W248F at the end of the S4 domain yielded a functional current, it underwent marked inactivation at positive voltages, rendering the channel non-functional. We demonstrate that by definition, none of the JLNS mutants operated in a dominant negative (DN) fashion. Instead, the JLNS mutants have impaired membrane trafficking, trapped in the endoplasmic reticulum (ER) and Cis-Golgi. The RWS mutants exhibited varied functional phenotypes. However, they can be summed up as exhibiting DN effects. Phenotypic differences between JLNS and RWS may stem from tissue-specific functional requirements of cardiac vs. inner ear non-sensory cells.
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Affiliation(s)
- Atefeh Mousavi Nik
- Department of Anesthesiology and Pain Medicine, Center for Neuroscience, School of Medicine, University of California, Davis Davis, CA, USA
| | - Somayeh Gharaie
- Department of Anesthesiology and Pain Medicine, Center for Neuroscience, School of Medicine, University of California, Davis Davis, CA, USA
| | - Hyo Jeong Kim
- Department of Anesthesiology and Pain Medicine, Center for Neuroscience, School of Medicine, University of California, Davis Davis, CA, USA
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7
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Winbo A, Stattin EL, Nordin C, Diamant UB, Persson J, Jensen SM, Rydberg A. Phenotype, origin and estimated prevalence of a common long QT syndrome mutation: a clinical, genealogical and molecular genetics study including Swedish R518X/KCNQ1 families. BMC Cardiovasc Disord 2014; 14:22. [PMID: 24552659 PMCID: PMC3942207 DOI: 10.1186/1471-2261-14-22] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 02/14/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The R518X/KCNQ1 mutation is a common cause of autosomal recessive (Jervell and Lange Nielsen Syndrome- JLNS) and autosomal dominant long QT syndrome (LQTS) worldwide. In Sweden p.R518X accounts for the majority of JLNS cases and is the second most common cause of LQTS. Here we investigate the clinical phenotype and origin of Swedish carriers of the p.R518X mutation. METHODS The study included 19 Swedish p.R518X index families, ascertained by molecular genetics methods (101 mutation-carriers, whereof 15 JLNS cases and 86 LQTS cases). In all families analyses included assessment of clinical data (symptoms, medications and manually measured electrocardiograms), genealogy (census records), haplotype (microsatellite markers) as well as assessment of mutation age and associated prevalence (ESTIAGE and DMLE computer software). RESULTS Clinical phenotype ranged from expectedly severe in JLNS to surprisingly benign in LQTS (QTc 576 ± 61 ms vs. 462 ± 34 ms, cumulative incidence of (aborted) cardiac arrest 47% vs. 1%, annual non-medicated incidence rate (aborted) cardiac arrest 4% vs. 0.04%).A common northern origin was found for 1701/1929 ancestors born 1650-1950. Historical geographical clustering in the coastal area of the Pite River valley was shown. A shared haplotype spanning the KCNQ1 gene was seen in 17/19 families. Mutation age was estimated to 28 generations (95% CI 19;41). A high prevalence of Swedish p.R518X heterozygotes was suggested (~1:2000-4000). CONCLUSIONS R518X/KCNQ1 occurs as a common founder mutation in Sweden and is associated with an unexpectedly benign phenotype in heterozygous carriers.
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Affiliation(s)
- Annika Winbo
- Department of Clinical Sciences, Pediatrics, Umeå University, Umeå, Sweden.
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Al-Aama J, Al-Ghamdi S, Bdier A, Wilde A, Bhuiyan ZA. De novomutation in theKCNQ1gene causal to Jervell and Lange-Nielsen syndrome. Clin Genet 2013; 86:492-5. [DOI: 10.1111/cge.12300] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 10/02/2013] [Accepted: 10/09/2013] [Indexed: 11/27/2022]
Affiliation(s)
- J.Y. Al-Aama
- Department of Genetic Medicine; King Abdulaziz University Hospital; Jeddah Saudi Arabia
- Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary Disorders; King Abdulaziz University; Jeddah Saudi Arabia
| | - S. Al-Ghamdi
- Department of Pediatric Cardiology; Prince Sultan Cardiac Center; Riyadh Saudi Arabia
| | - A.Y. Bdier
- Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary Disorders; King Abdulaziz University; Jeddah Saudi Arabia
| | - A.A.M. Wilde
- Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary Disorders; King Abdulaziz University; Jeddah Saudi Arabia
- Department of Cardiology, Academic Medical Center; University of Amsterdam; Amsterdam the Netherlands
| | - Zahurul A. Bhuiyan
- Laboratoire de Génétique Moléculaire, Service de Génétique Médicale; CHUV; Lausanne Switzerland
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Jackson HA, McIntosh S, Whittome B, Asuri S, Casey B, Kerr C, Tang A, Arbour LT. LQTS in Northern BC: homozygosity for KCNQ1 V205M presents with a more severe cardiac phenotype but with minimal impact on auditory function. Clin Genet 2013; 86:85-90. [PMID: 23844633 DOI: 10.1111/cge.12235] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/03/2013] [Accepted: 07/08/2013] [Indexed: 01/02/2023]
Abstract
Long QT syndrome (LQTS), a rare congenital cardiac condition associated with life-threatening ventricular arrhythmias is characterized by a prolonged QT interval on electrocardiograph corrected for heart rate [corrected QT (QTc)]. LQTS has been historically categorized into the autosomal dominant Romano-Ward syndrome (RWS) and the autosomal recessive Jervell and Lange-Nielsen syndrome (JLNS). JLNS is associated with prelingual sensorineural deafness. Both types of LQTS can be caused by mutations in channel genes (e.g. KCNQ1) responsible for potassium homeostasis in cardiac myocytes and cochlea. Autosomal dominant mutations often cause the RWS phenotype and homozygous or compound heterozygous mutations contribute to JLNS. Two First Nations communities in northern British Columbia are affected disproportionately with LQTS largely due to the V205M mutation in KCNQ1, however, the pathology and phenotypic expression for those V205M homozygous has been unknown. Here, we show that four V205M homozygous individuals have a significantly higher 'peak' QTc, and a more severe cardiac phenotype compared with 41 V205M heterozygous carriers and 57 first to third degree relatives without mutations. Given the lack of prelingual deafness the homozygous V205M LQTS patients present with a phenotype more typical of RWS than JLNS.
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Affiliation(s)
- H A Jackson
- Department of Medical Genetics and the Island Medical program, University of British Columbia, Victoria, British Columbia, Canada
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Iron-deficiency anaemia, gastric hyperplasia, and elevated gastrin levels due to potassium channel dysfunction in the Jervell and Lange-Nielsen Syndrome. Cardiol Young 2013; 23:325-34. [PMID: 22805636 DOI: 10.1017/s1047951112001060] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AIM We investigated extra-cardiac clinical symptoms and signs in the rare Jervell and Lange-Nielsen Syndrome, characterised by impaired KCNQ1 function, a gene essential for gastric acid secretion. METHODS All Swedish Jervell and Lange-Nielsen cases with double KCNQ1 mutations (14 cases) were investigated by medical record review, an interview, and were offered laboratory testing for iron-deficiency anaemia and gastrointestinal markers. RESULTS A history of iron-deficiency anaemia in 12 of 14 patients and subjective gastrointestinal symptoms in 13 of 14 patients was revealed. Previous endoscopy in five cases had revealed no case of coeliac or inflammatory bowel disease but three cases of mucosal hyperplasia/dysplasia. Current signs of anaemia or iron substitution were present in 9 of 12 tested cases. Elevated levels of gastrin in seven of nine cases, pepsinogen in six of seven cases, and faecal calprotectin in nine of nine cases were present. A significant correlation between elevated gastrin levels and concurrent iron-deficiency and/or anaemia was revealed (p-value 0.039). CONCLUSIONS A high frequency of extra-cardiac clinical symptoms and previous medical investigations was found. We propose that the Jervell and Lange-Nielsen Syndrome phenotypically includes gastrointestinal symptoms/signs and secondary iron-deficiency anaemia owing to hypochlorhydria on the basis of KCNQ1 mutations. The resultant elevated gastrin level is a potential risk factor for later gastrointestinal cancer. Clinical monitoring with regard to developing anaemia and hypergastrinaemia should be considered in the Jervell and Lange-Nielsen Syndrome.
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11
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Buniello A, Hardisty-Hughes RE, Pass JC, Bober E, Smith RJ, Steel KP. Headbobber: a combined morphogenetic and cochleosaccular mouse model to study 10qter deletions in human deafness. PLoS One 2013; 8:e56274. [PMID: 23457544 PMCID: PMC3572983 DOI: 10.1371/journal.pone.0056274] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 01/08/2013] [Indexed: 02/07/2023] Open
Abstract
The recessive mouse mutant headbobber (hb) displays the characteristic behavioural traits associated with vestibular defects including headbobbing, circling and deafness. This mutation was caused by the insertion of a transgene into distal chromosome 7 affecting expression of native genes. We show that the inner ear of hb/hb mutants lacks semicircular canals and cristae, and the saccule and utricle are fused together in a single utriculosaccular sac. Moreover, we detect severe abnormalities of the cochlear sensory hair cells, the stria vascularis looks severely disorganised, Reissner's membrane is collapsed and no endocochlear potential is detected. Myo7a and Kcnj10 expression analysis show a lack of the melanocyte-like intermediate cells in hb/hb stria vascularis, which can explain the absence of endocochlear potential. We use Trp2 as a marker of melanoblasts migrating from the neural crest at E12.5 and show that they do not interdigitate into the developing strial epithelium, associated with abnormal persistence of the basal lamina in the hb/hb cochlea. We perform array CGH, deep sequencing as well as an extensive expression analysis of candidate genes in the headbobber region of hb/hb and littermate controls, and conclude that the headbobber phenotype is caused by: 1) effect of a 648 kb deletion on distal Chr7, resulting in the loss of three protein coding genes (Gpr26, Cpmx2 and Chst15) with expression in the inner ear but unknown function; and 2) indirect, long range effect of the deletion on the expression of neighboring genes on Chr7, associated with downregulation of Hmx3, Hmx2 and Nkx1.2 homeobox transcription factors. Interestingly, deletions of the orthologous region in humans, affecting the same genes, have been reported in nineteen patients with common features including sensorineural hearing loss and vestibular problems. Therefore, we propose that headbobber is a useful model to gain insight into the mechanisms underlying deafness in human 10qter deletion syndrome.
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Affiliation(s)
- Annalisa Buniello
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | | | - Johanna C. Pass
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Eva Bober
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | | | - Karen P. Steel
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
- MRC Institute of Hearing Research, Nottingham, United Kingdom
- * E-mail:
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Giudicessi JR, Ackerman MJ. Prevalence and potential genetic determinants of sensorineural deafness in KCNQ1 homozygosity and compound heterozygosity. ACTA ACUST UNITED AC 2013; 6:193-200. [PMID: 23392653 DOI: 10.1161/circgenetics.112.964684] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND- Homozygous or compound heterozygous mutations in KCNQ1 cause Jervell and Lange-Nielsen syndrome, a rare, autosomal-recessive form of long-QT syndrome characterized by deafness, marked QT prolongation, and a high risk of sudden death. However, it is not understood why some individuals with mutations on both KCNQ1 alleles present without deafness. In this study, we sought to determine the prevalence and genetic determinants of this phenomenon in a large referral population of patients with long-QT syndrome. METHODS AND RESULTS- A retrospective analysis of all patients with long-QT syndrome evaluated from July 1998 to April 2012 was used to identify those with ≥1 KCNQ1 mutation. Of the 249 KCNQ1-positive patients identified, 15 (6.0%) harbored a rare putative pathogenic mutation on both KCNQ1 alleles. Surprisingly, 11 of these patients (73%) presented without the sensorineural deafness associated with Jervell and Lange-Nielsen syndrome. The degree of QT-interval prolongation and the number of breakthrough cardiac events were similar between patients with and without deafness. Interestingly, truncating mutations were more prevalent in patients with Jervell and Lange-Nielsen syndrome (79%) than in nondeaf patients (36%; P<0.001) derived from this study and those in the literature. CONCLUSIONS- In this study, we provide evidence that the recessive inheritance of a severe long-QT syndrome type 1 phenotype in the absence of an auditory phenotype may represent a more common pattern of long-QT syndrome inheritance than previously anticipated and that these cases should be treated as a higher-risk long-QT syndrome subset similar to their Jervell and Lange-Nielsen syndrome counterparts. Furthermore, mutation type may serve as a genetic determinant of deafness, but not cardiac expressivity, in individuals harboring ≥1 KCNQ1 mutation on each allele.
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Stattin EL, Boström IM, Winbo A, Cederquist K, Jonasson J, Jonsson BA, Diamant UB, Jensen SM, Rydberg A, Norberg A. Founder mutations characterise the mutation panorama in 200 Swedish index cases referred for Long QT syndrome genetic testing. BMC Cardiovasc Disord 2012; 12:95. [PMID: 23098067 PMCID: PMC3520728 DOI: 10.1186/1471-2261-12-95] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 10/10/2012] [Indexed: 11/24/2022] Open
Abstract
Background Long QT syndrome (LQTS) is an inherited arrhythmic disorder characterised by prolongation of the QT interval on ECG, presence of syncope and sudden death. The symptoms in LQTS patients are highly variable, and genotype influences the clinical course. This study aims to report the spectrum of LQTS mutations in a Swedish cohort. Methods Between March 2006 and October 2009, two hundred, unrelated index cases were referred to the Department of Clinical Genetics, Umeå University Hospital, Sweden, for LQTS genetic testing. We scanned five of the LQTS-susceptibility genes (KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2) for mutations by DHPLC and/or sequencing. We applied MLPA to detect large deletions or duplications in the KCNQ1, KCNH2, SCN5A, KCNE1, and KCNE2 genes. Furthermore, the gene RYR2 was screened in 36 selected LQTS genotype-negative patients to detect cases with the clinically overlapping disease catecholaminergic polymorphic ventricular tachycardia (CPVT). Results In total, a disease-causing mutation was identified in 103 of the 200 (52%) index cases. Of these, altered exon copy numbers in the KCNH2 gene accounted for 2% of the mutations, whereas a RYR2 mutation accounted for 3% of the mutations. The genotype-positive cases stemmed from 64 distinct mutations, of which 28% were novel to this cohort. The majority of the distinct mutations were found in a single case (80%), whereas 20% of the mutations were observed more than once. Two founder mutations, KCNQ1 p.Y111C and KCNQ1 p.R518*, accounted for 25% of the genotype-positive index cases. Genetic cascade screening of 481 relatives to the 103 index cases with an identified mutation revealed 41% mutation carriers who were at risk of cardiac events such as syncope or sudden unexpected death. Conclusion In this cohort of Swedish index cases with suspected LQTS, a disease-causing mutation was identified in 52% of the referred patients. Copy number variations explained 2% of the mutations and 3 of 36 selected cases (8%) harboured a mutation in the RYR2 gene. The mutation panorama is characterised by founder mutations (25%), even so, this cohort increases the amount of known LQTS-associated mutations, as approximately one-third (28%) of the detected mutations were unique.
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Affiliation(s)
- Eva-Lena Stattin
- Department of Medical Biosciences, Medical and Clinical Genetics, Umeå University, Umeå, Sweden.
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Winbo A, Stattin EL, Diamant UB, Persson J, Jensen SM, Rydberg A. Prevalence, mutation spectrum, and cardiac phenotype of the Jervell and Lange-Nielsen syndrome in Sweden. Europace 2012; 14:1799-806. [PMID: 22539601 DOI: 10.1093/europace/eus111] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
AIMS To explore the national prevalence, mutation spectrum, cardiac phenotype, and outcome of the uncommon Jervell and Lange-Nielsen syndrome (JLNS), associated with a high risk of sudden cardiac death. METHODS AND RESULTS A national inventory of clinical JLNS cases was performed. Genotype and area of origin were ascertained in index families. Retrospective clinical data were collected from medical records and interviews. We identified 19 cases in 13 Swedish families. A JLNS prevalence >1:200 000 was revealed (five living cases <10 years of age). The mutation spectrum consisted of eight KCNQ1 mutations, whereof p.R518X in 12/24 alleles. Geographic clustering of four mutations (20/24 alleles) and similarities to Norway's mutation spectrum were seen. A high prevalence of heterozygotes was suggested. Three paediatric cases on β-blockers since birth were as yet asymptomatic. Seven symptomatic cases had suffered an aborted cardiac arrest and four had died suddenly. QTc prolongation was significantly longer in symptomatic cases (mean 605 ± 62 vs. 518 ± 50 ms, P = 0.016). β-Blockers reduced, but did not abolish, cardiac events in any previously symptomatic case. β-Blocker type, dosage, and compliance probably affect outcome significantly. Implantable cardioverter-defibrillator therapy (ICD, n = 6) was associated with certain complications; however, no case of sudden death. CONCLUSION Founder effects could explain 83% of the Swedish JLNS mutation spectrum and probably contribute to the high JLNS prevalence found in preadolescent Swedish children. Due to the severe cardiac phenotype in JLNS, the importance of stringent β-blocker therapy and compliance, and consideration of ICD implantation in the case of therapy failure is stressed.
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Affiliation(s)
- Annika Winbo
- Division of Pediatrics, Department of Clinical Sciences, Pediatrics, Umeå University, 90185 Umeå, Sweden.
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A new homozygous mutation of the KCNQ1 gene associated with both Romano-Ward and incomplete Jervell Lange-Nielsen syndromes in two sisters. Heart Rhythm 2010; 7:531-3. [DOI: 10.1016/j.hrthm.2009.11.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 11/30/2009] [Indexed: 01/16/2023]
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Hedley PL, Jørgensen P, Schlamowitz S, Wangari R, Moolman-Smook J, Brink PA, Kanters JK, Corfield VA, Christiansen M. The genetic basis of long QT and short QT syndromes: A mutation update. Hum Mutat 2009; 30:1486-511. [DOI: 10.1002/humu.21106] [Citation(s) in RCA: 318] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Loonen AJM, Knoers NVAM, van Os CH, Deen PMT. Aquaporin 2 mutations in nephrogenic diabetes insipidus. Semin Nephrol 2008; 28:252-65. [PMID: 18519086 DOI: 10.1016/j.semnephrol.2008.03.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Water reabsorption in the renal collecting duct is regulated by the antidiuretic hormone vasopressin (AVP). When the vasopressin V2 receptor, present on the basolateral site of the renal principal cell, becomes activated by AVP, aquaporin-2 (AQP2) water channels will be inserted in the apical membrane, and in this fashion, water can be reabsorbed from the pro-urine into the interstitium. The essential role of the vasopressin V2 receptor and AQP2 in the maintenance of body water homeostasis became clear when it was shown that mutations in their genes cause nephrogenic diabetes insipidus, a disorder in which the kidney is unable to concentrate urine in response to AVP. This review describes the current knowledge on AQP2 mutations in nephrogenic diabetes insipidus.
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Affiliation(s)
- Anne J M Loonen
- Department of Physiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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Bhuiyan ZA, Momenah TS, Amin AS, Al-Khadra AS, Alders M, Wilde AA, Mannens MM. An intronic mutation leading to incomplete skipping of exon-2 in KCNQ1 rescues hearing in Jervell and Lange-Nielsen syndrome. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2008; 98:319-27. [DOI: 10.1016/j.pbiomolbio.2008.10.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Fodstad H, Swan H, Laitinen P, Piippo K, Paavonen K, Viitasalo M, Toivonen L, Kontula K. Four potassium channel mutations account for 73% of the genetic spectrum underlying long-QT syndrome (LQTS) and provide evidence for a strong founder effect in Finland. Ann Med 2004; 36 Suppl 1:53-63. [PMID: 15176425 DOI: 10.1080/17431380410032689] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND Mutations in five cardiac voltage-gated ion channel genes, including KCNQ1, HERG, SCN5A, KCNE1 and KCNE2, constitute the principal cause of inherited long-QT syndrome (LQTS). Typically, each family carries its own private mutation, and the disease manifests with varying phenotype and incomplete penetrance, even within particular families. We had previously identified 14 different LOTS-causing mutations in 92 Finnish families. AIM In order to complete the characterization of Finnish spectrum of LOTS genes, we conducted a systematic search for mutations in the five LOTS genes among 188 additional unrelated probands. METHODS The screening was performed by denaturing high-performance liquid chromatography (dHPLC) and DNA sequencing. RESULTS Nineteen novel and 12 previously described mutations were identified. Collectively, these data extend the number of molecularly defined affected Finnish LOTS families and patients at present to 150 and 939, respectively. Four presumable founder mutations (KCNQ1 G589D and IVS7-2A > G, HERG R176W and L552S) together account for as much as 73% of all established Finnish LQTS cases. CONCLUSIONS The extent of genetic homogeneity underlying LOTS in Finland is unique in the whole world, providing a major advantage for screening and presymptomatic diagnosis of LOTS, and constituting an excellent basis to study the role of genetic and non-genetic factors influencing phenotypic variability in this disease.
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Affiliation(s)
- Heidi Fodstad
- Research Program in Molecular Medicine, Biomedicum Helsinki, Finland
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Sander GE, Guillory GS, Giles TD. Noncardiac drugs and QTc interval prolongation: an often unrecognized risk factor for adverse cardiovascular outcomes. THE AMERICAN JOURNAL OF GERIATRIC CARDIOLOGY 2002; 11:197-202. [PMID: 11986537 DOI: 10.1111/j.1076-7460.2002.00882.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Gary E Sander
- Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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Wang Z, Li H, Moss AJ, Robinson J, Zareba W, Knilans T, Bowles NE, Towbin JA. Compound heterozygous mutations in KvLQT1 cause Jervell and Lange-Nielsen syndrome. Mol Genet Metab 2002; 75:308-16. [PMID: 12051962 DOI: 10.1016/s1096-7192(02)00007-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Jervell and Lange-Nielsen syndrome (JLNS) is characterized by sensorineural deafness, QT prolongation, abnormal T waves, ventricular tachyarrhythmias, and autosomal recessive inheritance. Previously homozygous mutations in the potassium channel-encoding genes, KvLQT1 (alpha-subunit) and KCNE1 (beta-subunit), have been described in consanguineous families with JLNS. We screened two nonconsanguineous families with JLNS for mutations in KvLQT1, using single-strand conformation polymorphism analysis, denaturing high-performance liquid chromatography, and DNA sequencing. In one family, a missense mutation was identified in exon 6 of KvLQT1 on the maternal side, resulting in a glycine to aspartic acid substitution at codon 269 (G269D). The apparently normal father had an incompletely penetrant missense mutation in exon 3 of KvLQT1, introducing a premature stop codon at position 171. In the other family, a missense mutation resulting in the substitution of asparagine for aspartic acid at codon 202 (D202N) was identified in the mother and maternal grandmother, who had QTc prolongation (borderline in the mother), while the father and paternal grandfather, who were clinically normal, had a deletion of nucleotide 585, resulting in a frameshift and premature termination. In both families, the proband inherited both mutations. In this report we provide evidence that not only homozygous but also compound heterozygous mutations in KvLQT1 may cause JLNS in nonconsanguineous families. Incomplete penetrance in individuals with mutations appears to be frequent, indicating a higher prevalence of mutations than estimated previously. Interestingly, mutations resulting in truncation of the protein appear to be benign, with heterozygous carriers being asymptomatic.
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Affiliation(s)
- Zhiqing Wang
- Department of Medicine (Cardiovascular Sciences), Baylor College of Medicine, Houston, TX 77030, USA
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Gilbert F. Disease genes and chromosomes: disease maps of the human genome. GENETIC TESTING 2001; 4:409-26. [PMID: 11216668 DOI: 10.1089/109065700750065180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- F Gilbert
- Weill Medical College of Cornell University, New York, NY 10021, USA.
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